utils: add osmo_escape_str()
To report invalid characters in identifiers, it is desirable to escape any
weird characters. Otherwise we might print stray newlines or control characters
in the log output.
ctrl_test.c already uses a print_escaped() function, which will be replaced by
osmo_escape_str() in a subsequent patch.
control_cmd.c will use osmo_escape_str() to log invalid identifiers.
Change-Id: Ic685eb63dead3967d01aaa4f1e9899e5461ca49a
diff --git a/src/utils.c b/src/utils.c
index 6cc823e..109aac0 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -467,4 +467,91 @@
return osmo_separated_identifiers_valid(str, NULL);
}
+/*! Return the string with all non-printable characters escaped.
+ * \param[in] str A string that may contain any characters.
+ * \param[in] len Pass -1 to print until nul char, or >= 0 to force a length.
+ * \param[inout] buf string buffer to write escaped characters to.
+ * \param[in] bufsize size of \a buf.
+ * \returns buf containing an escaped representation, possibly truncated, or str itself.
+ */
+const char *osmo_escape_str_buf(const char *str, int in_len, char *buf, size_t bufsize)
+{
+ int in_pos = 0;
+ int next_unprintable = 0;
+ int out_pos = 0;
+ char *out = buf;
+ /* -1 to leave space for a final \0 */
+ int out_len = bufsize-1;
+
+ if (!str)
+ return "(null)";
+
+ if (in_len < 0)
+ in_len = strlen(str);
+
+ while (in_pos < in_len) {
+ for (next_unprintable = in_pos;
+ next_unprintable < in_len && isprint((int)str[next_unprintable])
+ && str[next_unprintable] != '"'
+ && str[next_unprintable] != '\\';
+ next_unprintable++);
+
+ if (next_unprintable == in_len
+ && in_pos == 0)
+ return str;
+
+ while (in_pos < next_unprintable && out_pos < out_len)
+ out[out_pos++] = str[in_pos++];
+
+ if (out_pos == out_len || in_pos == in_len)
+ goto done;
+
+ switch (str[next_unprintable]) {
+#define BACKSLASH_CASE(c, repr) \
+ case c: \
+ if (out_pos > out_len-2) \
+ goto done; \
+ out[out_pos++] = '\\'; \
+ out[out_pos++] = repr; \
+ break
+
+ BACKSLASH_CASE('\n', 'n');
+ BACKSLASH_CASE('\r', 'r');
+ BACKSLASH_CASE('\t', 't');
+ BACKSLASH_CASE('\0', '0');
+ BACKSLASH_CASE('\a', 'a');
+ BACKSLASH_CASE('\b', 'b');
+ BACKSLASH_CASE('\v', 'v');
+ BACKSLASH_CASE('\f', 'f');
+ BACKSLASH_CASE('\\', '\\');
+ BACKSLASH_CASE('"', '"');
+#undef BACKSLASH_CASE
+
+ default:
+ out_pos += snprintf(&out[out_pos], out_len - out_pos, "\\%u", (unsigned char)str[in_pos]);
+ if (out_pos > out_len) {
+ out_pos = out_len;
+ goto done;
+ }
+ break;
+ }
+ in_pos ++;
+ }
+
+done:
+ out[out_pos] = '\0';
+ return out;
+}
+
+/*! Return the string with all non-printable characters escaped.
+ * Call osmo_escape_str_buf() with a static buffer.
+ * \param[in] str A string that may contain any characters.
+ * \param[in] len Pass -1 to print until nul char, or >= 0 to force a length.
+ * \returns buf containing an escaped representation, possibly truncated, or str itself.
+ */
+const char *osmo_escape_str(const char *str, int in_len)
+{
+ return osmo_escape_str_buf(str, in_len, namebuf, sizeof(namebuf));
+}
+
/*! @} */